Falling film heat exchanger with member to distribute liquid on external surfaces of tubes

Abstract

A falling film heat exchanger having a plurality of tubes is provided with a liquid distribution member surrounding each tube which directs liquid against the tube external wall to control the falling film flow and to form uniform films on each tube. The liquid can be a feed liquid or a heat exchange liquid such as a refrigerant.

What is claimed is: 
     
       1. A falling film heat exchanger comprising: a shell connected to vertically spaced apart horizontally arranged circular upper and lower tube sheets;   a plurality of vertically positioned parallel tubes, with each tube extending through and sealingly connected to a hole in each tube sheet;   a circular distribution plate spaced below the upper tube sheet and sealingly connected to the shell defining a heat exchange liquid distribution space, with said parallel tubes extending through oversized holes in the distribution plate;   a heat exchange liquid distribution member surrounding each tube in the distribution space joined at a lower end to the distribution plate around said oversized hole and means preventing liquid from flowing between the member upper end and the tube, said member having means which directs liquid, in the distribution space, against the tube external wall and permits flow of liquid to the tube external wall only from said member;   means to feed a heat exchange liquid to the distribution space and means to withdraw the heat exchange liquid from the shell side of the heat exchanger above the lower tube sheet; and   a feed liquid distribution box positioned above the upper tube sheet and means to deliver a feed liquid to the liquid distribution box.   
     
     
       2. A falling film heat exchanger according to claim 1 in which the member which directs liquid to the tube internal wall includes a plurality of spaced apart holes in the member which are sized so that the downwardly flowing liquid spreads out and distributes as a continuous liquid layer on the tube internal wall. 
     
     
       3. A falling film heat exchanger according to claim 2 in which the heat exchange liquid distribution member is a truncated conical shell having its upper end sealingly joined to the upper tube sheet. 
     
     
       4. A falling film heat exchanger according to claim 2 in which the holes are at an angle of about 0° to 80° measured from a plane horizontal to the tube axis. 
     
     
       5. A falling film heat exchanger according to claim 4 in which the angle is 20° to 80°. 
     
     
       6. A falling film heat exchanger according to claim 4 in which the angle is 40° to 70°.